Abstract

Spatial vision is severely degraded in the retinal periphery. Visual resolution, detection thresholds and positional judgments are all impaired. Several factors might limit spatial vision in the periphery: these include: increased optical and neural blur; reduced contrast sensitivity; shifts in “spatial scale”; spatial undersampling and increased positional uncertainty. By studying detection and position discrimination under a wide range of conditions including: low contrast, Gaussian blur, bandlimited masking, segmentation and Gaussian jitter, it is possible to estimate how each of these factors interact to limit peripheral spatial vision. Our studies suggest that at least two key factors operate to limit spatial vision in the periphery: i) a shift in spatial scale, which accounts for alterations in detection thresholds with increasing eccentricity, and ii) increases in the uncertainty of the position labels of the underlying spatial filters, which result in increased positional uncertainty with increasing eccentricity. The relationship between these factors, and plausible underlying anatomical and physiological mechanisms will be discussed.

© 1993 Optical Society of America